From what I remember when I did mine on my 300 Sport (a long time ago now), the plug and play depends a bit on whether it has the factory sat nav. Speaker wiring goes via the sat nav unit in the boot, so if you have it, you may need to DIY a bypass in that area. Mine didn’t have sat nav, so was relatively simple to bypass the factory amp in the passenger footwell. I did a double din replacement, with reversing camera, it worked very well.
I was going to do the same with the Gen 2 GS430 Sport, which did have the factory satnav. I’d bought the standard heater control from a non sat nav (sat nav incorporates the climate controls) but didn’t end up doing the swap in the end.